Infrared (IR) thermal came as can be used in a vast number of different situations, for example, when inspecting or surveying buildings or complex electrical systems, such as transformers, switchgears, etc., or water carrying systems such as heat exchangers, radiators, etc. IR cameras are used for capturing thermal information in an imaged view. Radiometric information based on this captured thermal radiation may then be displayed and viewed as thermal images on a display and may also be stored in the IR camera and subjected to subsequent analysis in order to, for example, detect faulty electrical wirings or couplings, leaking water pipes, or temperature deviations within a specific application.
Today, most of the analysis of the thermal images is performed by the user of the IR camera either on site by viewing the thermal images displayed live on the display or later on by storing the thermal images in the IR camera. In the case of performing a later analysis, the IR camera is generally arranged to store a number of still images or a video sequence of images in a memory unit or similar or to transmit images to a separate storage unit. The storage speed for storing a number of images in this manner is limited and it is a clear disadvantage for the user of the IR camera not to be able to store images at a desired speed, thus risking the loss of data. By compressing images that are displayed to a user of the system to reduce the amount of data for storage at each point in time, a higher number of images can be stored, but significant amount of information are generally lost through the compression, rendering detailed analysis difficult.
Another factor limiting the performance and storage capacity of an IR camera are system parameters such as the resolution or frame rate of detector elements used for detecting thermal radiation or transmission bandwidths between components within the camera itself or between the camera and a storage unit.
A problem in prior art, however, is to perform such processes without losses that render the resulting data insufficient for detailed analysis. When using video compression techniques are described for partitioning images into categories for different compression depending on similarities to other images of a sequence, but no efficient compression suited to properties of the IR camera system itself can be presented.
There is, therefore, a need for a more efficient processing of thermal information from an IR camera to overcome the difficulties outlined above.